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Vulnerability Details :

CVE-2026-42246

Summary
Assigner-GitHub_M
Assigner Org ID-a0819718-46f1-4df5-94e2-005712e83aaa
Published At-09 May, 2026 | 19:33
Updated At-12 May, 2026 | 02:29
Rejected At-
Credits

net-imap vulnerable to STARTTLS stripping via invalid response timing

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4.

Vendors
-
Not available
Products
-
Metrics (CVSS)
VersionBase scoreBase severityVector
Weaknesses
Attack Patterns
Solution/Workaround
References
HyperlinkResource Type
EPSS History
Score
Latest Score
-
N/A
No data available for selected date range
Percentile
Latest Percentile
-
N/A
No data available for selected date range
Stakeholder-Specific Vulnerability Categorization (SSVC)
▼Common Vulnerabilities and Exposures (CVE)
cve.org
Assigner:GitHub_M
Assigner Org ID:a0819718-46f1-4df5-94e2-005712e83aaa
Published At:09 May, 2026 | 19:33
Updated At:12 May, 2026 | 02:29
Rejected At:
▼CVE Numbering Authority (CNA)
net-imap vulnerable to STARTTLS stripping via invalid response timing

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4.

Affected Products
Vendor
Rubyruby
Product
net-imap
Versions
Affected
  • < 0.3.10
  • >= 0.4.0, < 0.4.24
  • >= 0.5.0, < 0.5.14
  • >= 0.6.0, < 0.6.4
Problem Types
TypeCWE IDDescription
CWECWE-392CWE-392: Missing Report of Error Condition
CWECWE-393CWE-393: Return of Wrong Status Code
CWECWE-754CWE-754: Improper Check for Unusual or Exceptional Conditions
CWECWE-636CWE-636: Not Failing Securely ('Failing Open')
CWECWE-841CWE-841: Improper Enforcement of Behavioral Workflow
Type: CWE
CWE ID: CWE-392
Description: CWE-392: Missing Report of Error Condition
Type: CWE
CWE ID: CWE-393
Description: CWE-393: Return of Wrong Status Code
Type: CWE
CWE ID: CWE-754
Description: CWE-754: Improper Check for Unusual or Exceptional Conditions
Type: CWE
CWE ID: CWE-636
Description: CWE-636: Not Failing Securely ('Failing Open')
Type: CWE
CWE ID: CWE-841
Description: CWE-841: Improper Enforcement of Behavioral Workflow
Metrics
VersionBase scoreBase severityVector
4.07.6HIGH
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Version: 4.0
Base score: 7.6
Base severity: HIGH
Vector:
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
Metrics Other Info
Impacts
CAPEC IDDescription
Solutions

Configurations

Workarounds

Exploits

Credits

Timeline
EventDate
Replaced By

Rejected Reason

References
HyperlinkResource
https://github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcp
x_refsource_CONFIRM
https://github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54cc0fd9618
x_refsource_MISC
https://github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdbb3eb8485e
x_refsource_MISC
https://github.com/ruby/net-imap/commit/97e2488fb5401a1783bddd959dde007d9fbce42c
x_refsource_MISC
https://github.com/ruby/net-imap/commit/f79d35bf5833f186e81044c57c843eda30c873da
x_refsource_MISC
https://github.com/ruby/net-imap/releases/tag/v0.3.10
x_refsource_MISC
https://github.com/ruby/net-imap/releases/tag/v0.4.24
x_refsource_MISC
https://github.com/ruby/net-imap/releases/tag/v0.5.14
x_refsource_MISC
Hyperlink: https://github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcp
Resource:
x_refsource_CONFIRM
Hyperlink: https://github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54cc0fd9618
Resource:
x_refsource_MISC
Hyperlink: https://github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdbb3eb8485e
Resource:
x_refsource_MISC
Hyperlink: https://github.com/ruby/net-imap/commit/97e2488fb5401a1783bddd959dde007d9fbce42c
Resource:
x_refsource_MISC
Hyperlink: https://github.com/ruby/net-imap/commit/f79d35bf5833f186e81044c57c843eda30c873da
Resource:
x_refsource_MISC
Hyperlink: https://github.com/ruby/net-imap/releases/tag/v0.3.10
Resource:
x_refsource_MISC
Hyperlink: https://github.com/ruby/net-imap/releases/tag/v0.4.24
Resource:
x_refsource_MISC
Hyperlink: https://github.com/ruby/net-imap/releases/tag/v0.5.14
Resource:
x_refsource_MISC
▼Authorized Data Publishers (ADP)
CISA ADP Vulnrichment
Affected Products
Metrics
VersionBase scoreBase severityVector
Metrics Other Info
Impacts
CAPEC IDDescription
Solutions

Configurations

Workarounds

Exploits

Credits

Timeline
EventDate
Replaced By

Rejected Reason

References
HyperlinkResource
Information is not available yet
▼National Vulnerability Database (NVD)
nvd.nist.gov
Source:security-advisories@github.com
Published At:09 May, 2026 | 20:16
Updated At:18 May, 2026 | 18:08

Net::IMAP implements Internet Message Access Protocol (IMAP) client functionality in Ruby. Prior to versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4, a man-in-the-middle attacker can cause Net::IMAP#starttls to return "successfully", without starting TLS. This issue has been patched in versions 0.3.10, 0.4.24, 0.5.14, and 0.6.4.

CISA Catalog
Date AddedDue DateVulnerability NameRequired Action
N/A
Date Added: N/A
Due Date: N/A
Vulnerability Name: N/A
Required Action: N/A
Metrics
TypeVersionBase scoreBase severityVector
Secondary4.07.6HIGH
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary3.17.4HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Type: Secondary
Version: 4.0
Base score: 7.6
Base severity: HIGH
Vector:
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Type: Primary
Version: 3.1
Base score: 7.4
Base severity: HIGH
Vector:
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CPE Matches

Ruby
ruby-lang
>>net\>>\
cpe:2.3:a:ruby-lang:net\:\:imap:*:*:*:*:*:ruby:*:*
Ruby
ruby-lang
>>net\>>\
cpe:2.3:a:ruby-lang:net\:\:imap:*:*:*:*:*:ruby:*:*
Ruby
ruby-lang
>>net\>>\
cpe:2.3:a:ruby-lang:net\:\:imap:*:*:*:*:*:ruby:*:*
Ruby
ruby-lang
>>net\>>\
cpe:2.3:a:ruby-lang:net\:\:imap:*:*:*:*:*:ruby:*:*
Weaknesses
CWE IDTypeSource
CWE-392Primarysecurity-advisories@github.com
CWE-393Primarysecurity-advisories@github.com
CWE-636Primarysecurity-advisories@github.com
CWE-754Primarysecurity-advisories@github.com
CWE-841Primarysecurity-advisories@github.com
CWE ID: CWE-392
Type: Primary
Source: security-advisories@github.com
CWE ID: CWE-393
Type: Primary
Source: security-advisories@github.com
CWE ID: CWE-636
Type: Primary
Source: security-advisories@github.com
CWE ID: CWE-754
Type: Primary
Source: security-advisories@github.com
CWE ID: CWE-841
Type: Primary
Source: security-advisories@github.com
Evaluator Description

Evaluator Impact

Evaluator Solution

Vendor Statements

References
HyperlinkSourceResource
https://github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54cc0fd9618security-advisories@github.com
Patch
https://github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdbb3eb8485esecurity-advisories@github.com
Patch
https://github.com/ruby/net-imap/commit/97e2488fb5401a1783bddd959dde007d9fbce42csecurity-advisories@github.com
Patch
https://github.com/ruby/net-imap/commit/f79d35bf5833f186e81044c57c843eda30c873dasecurity-advisories@github.com
Patch
https://github.com/ruby/net-imap/releases/tag/v0.3.10security-advisories@github.com
Release Notes
https://github.com/ruby/net-imap/releases/tag/v0.4.24security-advisories@github.com
Release Notes
https://github.com/ruby/net-imap/releases/tag/v0.5.14security-advisories@github.com
Release Notes
https://github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcpsecurity-advisories@github.com
Mitigation
Vendor Advisory
Hyperlink: https://github.com/ruby/net-imap/commit/0ede4c40b1523dfeaf95777b2678e54cc0fd9618
Source: security-advisories@github.com
Resource:
Patch
Hyperlink: https://github.com/ruby/net-imap/commit/24a4e770b43230286a05aa2a9746cdbb3eb8485e
Source: security-advisories@github.com
Resource:
Patch
Hyperlink: https://github.com/ruby/net-imap/commit/97e2488fb5401a1783bddd959dde007d9fbce42c
Source: security-advisories@github.com
Resource:
Patch
Hyperlink: https://github.com/ruby/net-imap/commit/f79d35bf5833f186e81044c57c843eda30c873da
Source: security-advisories@github.com
Resource:
Patch
Hyperlink: https://github.com/ruby/net-imap/releases/tag/v0.3.10
Source: security-advisories@github.com
Resource:
Release Notes
Hyperlink: https://github.com/ruby/net-imap/releases/tag/v0.4.24
Source: security-advisories@github.com
Resource:
Release Notes
Hyperlink: https://github.com/ruby/net-imap/releases/tag/v0.5.14
Source: security-advisories@github.com
Resource:
Release Notes
Hyperlink: https://github.com/ruby/net-imap/security/advisories/GHSA-vcgp-9326-pqcp
Source: security-advisories@github.com
Resource:
Mitigation
Vendor Advisory

Change History

0
Information is not available yet

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EPSS-0.07% / 22.42%
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ShareView Details
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Known To Be Used In Ransomware Campaigns?-Not Available
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Details not found